Mammary Gland Function During Involution

Hurley, W.L.

doi:10.3168/jds.s0022-0302(89)79276-6

Cited by 198 publications

(183 citation statements)

References 73 publications

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“…In cows not milked for 48 h, Holst et al [35] observed an accumulation of Golgi vesicles and lipid droplets in mammary epithelial cells. If colchicine (which is known to destructure the cytoskeleton) was injected via the teat canal, similar effects were observed [36]. According to Stelwagen [37], the migration of secretory vesicles could be disturbed by an accumulation of milk in the mammary alveoli because of modifications to the cytoskeleton orchestrated by the opening of tight junctions.…”

Section: Metabolic and Secretion Activitiesmentioning

confidence: 80%

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

et al. 2006

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-The aim of this review is to better understand the regulation of milk yield in response to once-daily milking and feed restriction. Glucose is the principal precursor for the synthesis of lactose (a major osmotic agent in milk), and participates in determining the milk volume produced. When applying these two breeding factors, reductions in milk yield are associated with a reduction in milk lactose yield and in the arterial flow of glucose, due to a decrease in the mammary blood flow. The ability of the udder to extract glucose is altered with once-daily milking but not necessarily with feed restriction. Lactose synthesis is down-regulated in response to once-daily milking and feed restriction but the percentage of the extracted glucose which is converted into lactose is differently affected in response to treatments. No marked change is observed with once daily milking whereas this would be increased with feed restriction and in contrast, depressed with fasting. milk yield / glucose / mammary gland / uptake / metabolic fate / ruminants

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Section: Metabolic and Secretion Activitiesmentioning

confidence: 80%

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

et al. 2006

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“…The MECs in ruminants do not regress to the same extent as occurs in rodent mammary glands, and apparently some synthetic and secretory activity of these cells are maintained throughout the dry period (Holst et al, 1987;Sordillo, 1987;Sordillo and Nickerson, 1988). Sloughing of apoptotic epithelial cells into the alveolar lumen and detachment from the basement membrane observed during the first 2 weeks of involution in rat and mice are not detectable during dry period in dairy cows (Sordillo and Nickerson, 1988;Hurley, 1989;Capuco et al, 1997). Although mammary cell loss does not occur extensively during a standard dry period, tissue remodeling including changes in cell populations, alveolar structure and syntheses of extracellular matrix occur extensively (Holst et al, 1987;Hurley, 1989;Capuco et al, 1997).…”

Section: Altered Dry Periodsmentioning

confidence: 99%

“…Sloughing of apoptotic epithelial cells into the alveolar lumen and detachment from the basement membrane observed during the first 2 weeks of involution in rat and mice are not detectable during dry period in dairy cows (Sordillo and Nickerson, 1988;Hurley, 1989;Capuco et al, 1997). Although mammary cell loss does not occur extensively during a standard dry period, tissue remodeling including changes in cell populations, alveolar structure and syntheses of extracellular matrix occur extensively (Holst et al, 1987;Hurley, 1989;Capuco et al, 1997). Thus, extensive cell turnover occurs during the dry period and the number of epithelial cells rapidly increases during the last 2 months of gestation (Capuco et al, 1997).…”

Section: Altered Dry Periodsmentioning

confidence: 99%

Effects of continuous lactation and short dry periods on mammary function and animal health

Collier

Annen-Dawson

Pezeshki

2012

Animal

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The dry period is required to facilitate cell turnover in the bovine mammary gland in order to optimize milk yield in the next lactation. Traditionally, an 8-week dry period has been a standard management practice for dairy cows based on retrospective analyses of milk yields following various dry period lengths. However, as milk production per cow has increased, transitioning cows from the nonlactating state to peak milk yield has grown more problematic. This has prompted new studies on dry period requirements for dairy cows. These studies indicate a clear parity effect on dry period requirement. First parity animals require a 60-day dry period, whereas lactations following later parities demonstrate no negative impact with 30-day dry period or even eliminating the dry period when somatotropin (ST) is also used to maintain milk yields. Shortened dry periods in first parity animals were associated with reduced mammary cell turnover during the dry period and early lactation and increased numbers of senescent cells and reduced functionality of lactating alveolar mammary cells postpartum. Use of ST and increased milking frequency postpartum reduced the impact of shortened dry periods. The majority of new intramammary infections occur during the dry period and persist into the following lactation. There is therefore the possibility of altering mastitis incidence by modifying or eliminating the dry period in older parity animals. As the composition of mammary secretions including immunoglobulins may be reduced when the dry period is reduced or eliminated, there is the possibility that the immune status of cows during the peripartum period is influenced by the length of the dry period.

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“…İn-volusyonun erken dönemlerinde süte özel olan yağ, laktoz, kazein, α-laktalbumin, β-laktoglobulin miktarları azalırken diğer komponentler olan lökosit, hidrolitik enzimler, immünglobülinler, serum albumin ve laktoferrin ise involusyon boyunca artar ki bu sütteki toplam protein miktarının artışına neden olur. Memede laktoferrin miktarındaki artış involusyonun da aktif olduğunu göstermektedir (7,21). Doğumdan sonraki ilk 48 saat içinde iki önemli koruyucu protein olan laktoferrin ve sIgA miktarı yüksektir.…”

Section: Tartışma Ve Sonuçunclassified

Laktasyon periyodundaki Ankara keçilerinde süt ve serum laktoferrin düzeyleri

Gülcan¹

2004

Ankara Üniversitesi Veteriner Fakültesi Dergisi

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Özet: Ankara keçilerindeki laktoferrinin süt ve kan serum düzeyleri laktasyon periyodu boyunca ELISA ile belirlenmiş ve süt serumu ile kan serum proteinleri poliakrilamid jel elektroforezde incelenmiştir. Toplam 18 baş Ankara keçisinden laktasyonun 1., 2., 3., 5., 7., 11., 15., 20., 30., 45. ve 60. günlerinde süt ve kan örnekleri alınmıştır. Mastitis indikatör kağıt ile kontrol edilen süt numunelerinde direk somatik hücre sayımı yapılmıştır. Kesilmiş süt proteinleriyle kan serum proteinlerinin % dağılımları poliakrilamid jel elektroforezde incelenmiştir. Elektroforez bantlarının değerlendirilmesinde yaklaşık 78.000 dalton molekül ağırlığındaki proteinin süt serumundaki dansitometrik % dağılımı laktasyonun başlangıcında daha düşükken, laktasyon periyodu boyunca giderek artmış ve 2 katı seviyesine ulaşmıştır. Elektroforez bantlarının değerlendirilmesinde yaklaşık 78.000 dalton molekül ağırlığındaki serum proteininin dansitometrik % dağılımı, ilk üç gün istatistik olarak laktasyonun diğer günlerine göre yüksek bulunmuştur. Laktasyonun 3. gününden itibaren ise giderek azalan bir % dağılım göstermiştir. Süt ve serumdaki laktoferrin düzeyleri ELISA ile belirlenmiştir. Laktasyon süresince süt ve serum laktoferrin miktarları ELISA yönteminde sırasıyla ortalama 39.43-63.97 µg/ml ve 2.17-3.08 µg/ml arasında değişim göstermiştir. Ankara keçilerinde süt ve serum laktoferrin düzeyleri laktasyon periyodu boyunca istatistik olarak önemli bir değişim göstermemiştir. Tiftik verimi yönüyle yetiştirilen Ankara keçilerinde süt ve serum laktoferrin düzeyleri literatür verilerindeki domuz, inek, köpek, koyun ve keçi gibi laktasyondaki diğer hayvanların süt ve serum laktoferrin düzeylerine göre çok düşük bulunmuştur.Anahtar sözcükler: Ankara keçisi, demir bağlayan glikoprotein, laktoferrin, süt proteinleriMilk and serum lactoferrin levels in Angora Goats during lactation period Summary: Milk and serum lactoferrin levels which is important for human and animal healt because of its several properties during lactation period in Angora Goats were determined. Milk and blood samples have been taken from 18 Angora Goats in 1 st , 2 nd , 3 rd , 5 th , 7 th , 11 th , 15 th , 20 th , 30 th , 45 th and 60 th days of lactation. In milk samples, somatic cell counts have been performed following the control of milk samples using indicator papers for mastitis. Fat and casein were removed from milk samples by centrifugation and using glacial acetic acit precipitation respectively. Following that proteins were precipitated from milk serum by amonium sulphate precipitation. Obtained whey proteins of milk and blood serum proteins were applied to Polyaccrilamide Gel Electrophoresis (SDS-PAGE) system. Milk and serum lactoferrin levels were detected using ELISA. Dansitometric analysis of whey protein bands on the gels showed that a protein with approximately 78.000 dalton molecular weight showed a decreased percentage at the beginning of lactation. This 78.000 dalton protein was gradually increased towards the end of lactation up to the two fold increase. ...

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Mammary Gland Function During Involution

Cited by 198 publications

References 73 publications

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

Effects of continuous lactation and short dry periods on mammary function and animal health

Laktasyon periyodundaki Ankara keçilerinde süt ve serum laktoferrin düzeyleri

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